Along with the progress of information technology (IT) in various fields in recent years, there has been increasing needs for data centers that provide lines connected to a network and maintenance and management services to customers.
Typically, because a number of servers are placed in a server room of data centers, a large amount of heat is generated therefrom. To operate servers normally in such a server room, it is required to perform air-conditioning on a server room appropriately and to maintain the server room within a predetermined range of environmental conditions.
As a technology for cooling a room in which a number of computers are placed, such as a server room of data centers, there has been developed an air-conditioning system in which air sucked from a lower space of a room is blown out to an upper space, whereby the air is caused to be sucked from an upper part of a server rack.
By using the technology, it is possible to reduce the temperature gradient of the whole server room and the fluctuation in the supply air temperature. Therefore, efficient air-conditioning control can be achieved.
However, if a load of a target to be air-conditioned, such as a server room of a data center, is information devices, there exists characteristics different from that of a typical building. For example, for such target to be air-conditioned, most of the load is a sensible heat load, the preset temperature and humidity only needs to fall within a predetermined range, and no air ventilation for preventing increase in CO2 concentration is required because the load generates no CO2. However, conventionally there is a disadvantage in that no air-conditioning control is performed in accordance with these characteristics, thereby resulting in consumption of unnecessary energy.